Question

How do you evaluate 78+87?

Answer 1

Let there be two digit number ab

ab+ba=(10a+b)+(10b+a)

ab+ba=11a+11b=11(a+b)

ab+ba/a+b=11

Here,78 and 87 are numbers that can be obtained by reversing each other.

Sum of numbers =165

Sum of digits= 15

165/15=11